<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style type="text/css">
        li {
            margin-top: 10px;
        }
        li:before {
            content: "";
            padding: 12px;
            font-size: 0px;
            vertical-align: middle;
            margin-right: 10px;
        }
        .icon1:before {
            background-image: url("img/icon1.png");
        }
        .icon2:before {
            background-image: url("img/icon2.png");
        }
        .icon3:before {
            background-image: url("img/icon3.png");
        }
    </style>
</head>
<body>
    <ul>
        <li class="icon1">腾讯企业邮箱</li>
        <li class="icon2">知您网</li>
        <li class="icon3">码云</li>
    </ul>
</body>
</html>